Offsetting of Assets and Liabilities (Offsetting of Derivative Liabilities and Securities Sold Under Agreements to Repurchase) (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	$ 2,243.8	$ 4,841.3
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	1,427.1	4,199.6
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	816.7	641.7
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	0.0	0.0
NET AMOUNT	816.7	641.7
Total Derivatives Not Subject to a Master Netting Arrangement
Total Derivatives Not Subject to a Master Netting Arrangement	939.7	317.1
Offsetting Derivative Liabilities [Abstract]
GROSS RECOGNIZED LIABILITIES	3,183.5	5,158.4
Derivative Liabilities	1,756.4	958.8
NET AMOUNT	1,756.4	958.8
Securities Sold under Agreements to Repurchase
GROSS RECOGNIZED LIABILITIES	65,313.9	65,374.8
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	64,978.2	64,912.8
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	335.7	462.0
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	335.7	462.0
NET AMOUNT	0.0	0.0
Foreign Exchange Contracts | Over the Counter Derivative
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	1,810.2	4,392.7
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	1,423.0	4,197.3
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	387.2	195.4
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	0.0	0.0
NET AMOUNT	387.2	195.4
Interest Rate Swap Contracts | Over the Counter Derivative
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	404.1	421.2
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	4.1	2.3
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	400.0	418.9
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	0.0	0.0
NET AMOUNT	400.0	418.9
Interest Rate Swap Contracts | Interest Rate Swaps Exchange Cleared
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES		0.2
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET		0.0
NET AMOUNTS PRESENTED IN THE BALANCE SHEET		0.2
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET		0.0
NET AMOUNT		0.2
Other Financial Derivatives | Other Financial Derivatives
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	29.5	27.2
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	0.0	0.0
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	29.5	27.2
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	0.0	0.0
NET AMOUNT	$ 29.5	$ 27.2